This invention relates to a ship of the kind designed to achieve high speed through the use of multiple, low-wave making resistance, submerged hullform pods.
This invention relates particularly to a ship which is constructed to have stable operation during maneuvers with and without a payload.
My prior U.S. Pat. No. 5,592,895 issued Jan. 14, 1997; my U.S. Pat. No. 4,552,083 issued Nov. 12, 1985 and my U.S. Pat. No. 4,798,153 issued Jan. 17, 1989 illustrate and describe a small water plane area high speed ship of the general kind to which this invention relates.
Ships of this kind (ships which are designed to achieve high speed through the use of multiple, low-wave making resistance, submerged hullform pods) can present unique problems in operations (particularly in operations at high speeds with substantial payloads) as compared to the operation of a conventional monohull ship operating at lower speeds.
For example, one unique problem that can occur with a ship of this kind is a problem of undesired roll out of the ship in a turn. The roll out can result from an inertial moment produced by an elevated center of gravity of the ship.
In prior art ships of this kind fins associated with the submerged hullform pods were used to steer the ship and were also used to control roll of the ship. In the prior art the functions (steering and roll control) were independent. If the fins were positioned to control roll, the settings substantially reduced the steering to the point where it could be necessary to turn off roll control in order to get steering; and, when trying to control roll, the ship could be caused to change heading. The fore and aft fins of prior art ships could be set to offset the rolling moment caused by each other, but these prior art ships had no control power remaining to counteract the roll due to inertia. The prior art fore and aft fins were, in effect, adversely coupled so that using the fins to steer produced a roll moment which was additive to the roll moment produced by the inertia of the ship.
A proper load balance can be another problem.
Efficient and effective use of control fins on the associated submerged hullform pods can be another unique problem with ships of this kind.
It is a primary object of the present invention to eliminate or to overcome such unique problems by novel methods and apparatus of the present invention.
It is a specific object of the present invention to construct and to operate fin means on each pod which are effective to provide the turning and to counteract the inertia moment produced during the turning of the ship so that the ship does not roll out of the turn.
The ship of the present invention is designed to achieve high speed through the use of multiple, low wave-making resistance, submerged hullform pods.
The ship of the present invention comprises a superstructure which is constructed for operation above the surface of the water.
A first pair of transversely spaced fore struts extend downwardly from the superstructure.
A second pair of transversely spaced aft struts extend downwardly from the superstructure. The second pair of aft struts is longitudinally spaced from the first pair of fore struts.
A low wave-making resistance hullform pod is attached to each strut to provide a pair of transversely spaced fore pods and a pair of transversely spaced aft pods located beneath the superstructure.
In one embodiment of the invention a propulsion propeller is located at the rear of each pod on at least one pair of said fore and aft pods.
In another embodiment of the invention a propulsion propeller is located at the front of each pod on at least one pair of the fore and aft pods.
In another embodiment of the invention a propulsion water jet is located at the rear of each pod on at least one pair of the fore and aft pods.
Each pod is configured to have a longitudinal length which is shorter than the length of the ship and a transverse diameter which is large enough to enable the pods to provide all or substantially all of the buoyancy required to maintain the superstructure above the surface of the water during the propulsion of the ship.
Each pod has one or more fins operatively associated with the pod. Each fin is movable with respect to the associated pod (under the control of the operator of the ship or under automatic control) for controlling the ship during maneuvers and/or for providing additional lift as needed.
The movement of the fin with respect to the pod may be a tilting of the fin, or the movement may be an extension of the fin outwardly of the pod or a retraction of the fin inwardly of the pod, depending upon the specific embodiment of the present invention.
It is an important feature of the present invention that the fins on the pods are constructed and are effective to provide the turning and to counteract the inertia moment produced during the turning of the ship so that the ship does not roll out of a turn. The fin and pod constructions of the present invention produce flat turns or rolls into turns.
In another embodiment of the present invention a fifth pod is used for additional buoyancy and load balancing.
The payload of a ship may vary, and larger payloads may require more buoyancy. The use of a fifth pod provides additional load carrying capacity. In the present invention the fifth pod can be moved fore-or-aft or side-to-side to balance the location of the payload on the ship.
The fifth pod can be constructed to have a propulsion propeller (and a self-contained motor and driver mechanism located entirely within the pod) for additional propulsion capability.
In another specific embodiment of the present invention the pod can be retracted when it is not needed, such as, for example, after a part of the payload has been expended or off-loaded. This lowers the drag.
The individual pods are each large enough to enable the motor and all drive mechanism to be contained within the interior of the pod. This has a benefit in permitting all of the weight of the drive mechanism to be located forward in the ship to provide better load balance (with the payload placed on the aft part of the superstructure of the ship). This permits the center of gravity to be maintained close to the center of buoyancy of the ship.
In other specific embodiments of the present invention all of the fins, instead of being pivotal, are maintained at a set angle, but the length of the fin projecting from the associated pod is varied by extending the fin outwardly of the pod and by retracting the fin inwardly into the pod. The fin is driven back and forth under the control of the operator to create the amount of side force needed for maneuvers and/or to control the amount of lift that might be needed during different operations of the ship. The amount of power needed to extend or to retract a fin is less than the amount of power needed to tilt a fin with respect to the pod. Less structure is required and the mechanism is simplified.
In a specific embodiment of the present invention each pod has a fin which can be projected from and retracted into the one side of the pod and another fin which can be projected from and retracted into the other side of the pod. This embodiment permits using the best fin (the outboard fin or the inboard fin) for a particular purpose. This embodiment also permits maximum effectiveness by using both fins on a single pod.
Ship constructions, methods and apparatus which incorporate the features described above and which are effective to function as described above constitute further, specific objects of the invention.
Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings, which by way of illustration, show preferred embodiments of the present invention and the principles thereof and what are now considered to be the best modes contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.